drivers/regulator/max8952.c

   1 /*
   2  * max8952.c - Voltage and current regulation for the Maxim 8952
   3  *
   4  * Copyright (C) 2010 Samsung Electronics
   5  * MyungJoo Ham <myungjoo.ham@samsung.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/i2c.h>
  25 #include <linux/err.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/regulator/driver.h>
  28 #include <linux/regulator/max8952.h>
  29 #include <linux/mutex.h>
  30 #include <linux/gpio.h>
  31 #include <linux/io.h>
  32 #include <linux/slab.h>
  33
  34 /* Registers */
  35 enum {
  36         MAX8952_REG_MODE0,
  37         MAX8952_REG_MODE1,
  38         MAX8952_REG_MODE2,
  39         MAX8952_REG_MODE3,
  40         MAX8952_REG_CONTROL,
  41         MAX8952_REG_SYNC,
  42         MAX8952_REG_RAMP,
  43         MAX8952_REG_CHIP_ID1,
  44         MAX8952_REG_CHIP_ID2,
  45 };
  46
  47 struct max8952_data {
  48         struct i2c_client       *client;
  49         struct device           *dev;
  50         struct mutex            mutex;
  51         struct max8952_platform_data *pdata;
  52         struct regulator_dev    *rdev;
  53
  54         bool vid0;
  55         bool vid1;
  56         bool en;
  57 };
  58
  59 static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
  60 {
  61         int ret = i2c_smbus_read_byte_data(max8952->client, reg);
  62         if (ret > 0)
  63                 ret &= 0xff;
  64
  65         return ret;
  66 }
  67
  68 static int max8952_write_reg(struct max8952_data *max8952,
  69                 u8 reg, u8 value)
  70 {
  71         return i2c_smbus_write_byte_data(max8952->client, reg, value);
  72 }
  73
  74 static int max8952_voltage(struct max8952_data *max8952, u8 mode)
  75 {
  76         return (max8952->pdata->dvs_mode[mode] * 10 + 770) * 1000;
  77 }
  78
  79 static int max8952_list_voltage(struct regulator_dev *rdev,
  80                 unsigned int selector)
  81 {
  82         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  83
  84         if (rdev_get_id(rdev) != 0)
  85                 return -EINVAL;
  86
  87         return max8952_voltage(max8952, selector);
  88 }
  89
  90 static int max8952_is_enabled(struct regulator_dev *rdev)
  91 {
  92         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  93         return max8952->en;
  94 }
  95
  96 static int max8952_enable(struct regulator_dev *rdev)
  97 {
  98         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
  99
 100         /* If not valid, assume "ALWAYS_HIGH" */
 101         if (gpio_is_valid(max8952->pdata->gpio_en))
 102                 gpio_set_value(max8952->pdata->gpio_en, 1);
 103
 104         max8952->en = true;
 105         return 0;
 106 }
 107
 108 static int max8952_disable(struct regulator_dev *rdev)
 109 {
 110         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
 111
 112         /* If not valid, assume "ALWAYS_HIGH" -> not permitted */
 113         if (gpio_is_valid(max8952->pdata->gpio_en))
 114                 gpio_set_value(max8952->pdata->gpio_en, 0);
 115         else
 116                 return -EPERM;
 117
 118         max8952->en = false;
 119         return 0;
 120 }
 121
 122 static int max8952_get_voltage(struct regulator_dev *rdev)
 123 {
 124         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
 125         u8 vid = 0;
 126
 127         if (max8952->vid0)
 128                 vid += 1;
 129         if (max8952->vid1)
 130                 vid += 2;
 131
 132         return max8952_voltage(max8952, vid);
 133 }
 134
 135 static int max8952_set_voltage(struct regulator_dev *rdev,
 136                                int min_uV, int max_uV, unsigned *selector)
 137 {
 138         struct max8952_data *max8952 = rdev_get_drvdata(rdev);
 139         s8 vid = -1, i;
 140
 141         if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
 142                         !gpio_is_valid(max8952->pdata->gpio_vid0)) {
 143                 /* DVS not supported */
 144                 return -EPERM;
 145         }
 146
 147         for (i = 0; i < MAX8952_NUM_DVS_MODE; i++) {
 148                 int volt = max8952_voltage(max8952, i);
 149
 150                 /* Set the voltage as low as possible within the range */
 151                 if (volt <= max_uV && volt >= min_uV)
 152                         if (vid == -1 || max8952_voltage(max8952, vid) > volt)
 153                                 vid = i;
 154         }
 155
 156         if (vid >= 0 && vid < MAX8952_NUM_DVS_MODE) {
 157                 max8952->vid0 = (vid % 2 == 1);
 158                 max8952->vid1 = (((vid >> 1) % 2) == 1);
 159                 *selector = vid;
 160                 gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
 161                 gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
 162         } else
 163                 return -EINVAL;
 164
 165         return 0;
 166 }
 167
 168 static struct regulator_ops max8952_ops = {
 169         .list_voltage           = max8952_list_voltage,
 170         .is_enabled             = max8952_is_enabled,
 171         .enable                 = max8952_enable,
 172         .disable                = max8952_disable,
 173         .get_voltage            = max8952_get_voltage,
 174         .set_voltage            = max8952_set_voltage,
 175         .set_suspend_disable    = max8952_disable,
 176 };
 177
 178 static struct regulator_desc regulator = {
 179         .name           = "MAX8952_VOUT",
 180         .id             = 0,
 181         .n_voltages     = MAX8952_NUM_DVS_MODE,
 182         .ops            = &max8952_ops,
 183         .type           = REGULATOR_VOLTAGE,
 184         .owner          = THIS_MODULE,
 185 };
 186
 187 static int __devinit max8952_pmic_probe(struct i2c_client *client,
 188                 const struct i2c_device_id *i2c_id)
 189 {
 190         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 191         struct max8952_platform_data *pdata = client->dev.platform_data;
 192         struct max8952_data *max8952;
 193
 194         int ret = 0, err = 0;
 195
 196         if (!pdata) {
 197                 dev_err(&client->dev, "Require the platform data\n");
 198                 return -EINVAL;
 199         }
 200
 201         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
 202                 return -EIO;
 203
 204         max8952 = kzalloc(sizeof(struct max8952_data), GFP_KERNEL);
 205         if (!max8952)
 206                 return -ENOMEM;
 207
 208         max8952->client = client;
 209         max8952->dev = &client->dev;
 210         max8952->pdata = pdata;
 211         mutex_init(&max8952->mutex);
 212
 213         max8952->rdev = regulator_register(&regulator, max8952->dev,
 214                         &pdata->reg_data, max8952);
 215
 216         if (IS_ERR(max8952->rdev)) {
 217                 ret = PTR_ERR(max8952->rdev);
 218                 dev_err(max8952->dev, "regulator init failed (%d)\n", ret);
 219                 goto err_reg;
 220         }
 221
 222         max8952->en = !!(pdata->reg_data.constraints.boot_on);
 223         max8952->vid0 = (pdata->default_mode % 2) == 1;
 224         max8952->vid1 = ((pdata->default_mode >> 1) % 2) == 1;
 225
 226         if (gpio_is_valid(pdata->gpio_en)) {
 227                 if (!gpio_request(pdata->gpio_en, "MAX8952 EN"))
 228                         gpio_direction_output(pdata->gpio_en, max8952->en);
 229                 else
 230                         err = 1;
 231         } else
 232                 err = 2;
 233
 234         if (err) {
 235                 dev_info(max8952->dev, "EN gpio invalid: assume that EN"
 236                                 "is always High\n");
 237                 max8952->en = 1;
 238                 pdata->gpio_en = -1; /* Mark invalid */
 239         }
 240
 241         err = 0;
 242
 243         if (gpio_is_valid(pdata->gpio_vid0) &&
 244                         gpio_is_valid(pdata->gpio_vid1)) {
 245                 if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0"))
 246                         gpio_direction_output(pdata->gpio_vid0,
 247                                         (pdata->default_mode) % 2);
 248                 else
 249                         err = 1;
 250
 251                 if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1"))
 252                         gpio_direction_output(pdata->gpio_vid1,
 253                                 (pdata->default_mode >> 1) % 2);
 254                 else {
 255                         if (!err)
 256                                 gpio_free(pdata->gpio_vid0);
 257                         err = 2;
 258                 }
 259
 260         } else
 261                 err = 3;
 262
 263         if (err) {
 264                 dev_warn(max8952->dev, "VID0/1 gpio invalid: "
 265                                 "DVS not avilable.\n");
 266                 max8952->vid0 = 0;
 267                 max8952->vid1 = 0;
 268                 /* Mark invalid */
 269                 pdata->gpio_vid0 = -1;
 270                 pdata->gpio_vid1 = -1;
 271
 272                 /* Disable Pulldown of EN only */
 273                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
 274
 275                 dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1"
 276                                 " do not have proper controls.\n");
 277         } else {
 278                 /*
 279                  * Disable Pulldown on EN, VID0, VID1 to reduce
 280                  * leakage current of MAX8952 assuming that MAX8952
 281                  * is turned on (EN==1). Note that without having VID0/1
 282                  * properly connected, turning pulldown off can be
 283                  * problematic. Thus, turn this off only when they are
 284                  * controllable by GPIO.
 285                  */
 286                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
 287         }
 288
 289         max8952_write_reg(max8952, MAX8952_REG_MODE0,
 290                         (max8952_read_reg(max8952,
 291                                           MAX8952_REG_MODE0) & 0xC0) |
 292                         (pdata->dvs_mode[0] & 0x3F));
 293         max8952_write_reg(max8952, MAX8952_REG_MODE1,
 294                         (max8952_read_reg(max8952,
 295                                           MAX8952_REG_MODE1) & 0xC0) |
 296                         (pdata->dvs_mode[1] & 0x3F));
 297         max8952_write_reg(max8952, MAX8952_REG_MODE2,
 298                         (max8952_read_reg(max8952,
 299                                           MAX8952_REG_MODE2) & 0xC0) |
 300                         (pdata->dvs_mode[2] & 0x3F));
 301         max8952_write_reg(max8952, MAX8952_REG_MODE3,
 302                         (max8952_read_reg(max8952,
 303                                           MAX8952_REG_MODE3) & 0xC0) |
 304                         (pdata->dvs_mode[3] & 0x3F));
 305
 306         max8952_write_reg(max8952, MAX8952_REG_SYNC,
 307                         (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
 308                         ((pdata->sync_freq & 0x3) << 6));
 309         max8952_write_reg(max8952, MAX8952_REG_RAMP,
 310                         (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
 311                         ((pdata->ramp_speed & 0x7) << 5));
 312
 313         i2c_set_clientdata(client, max8952);
 314
 315         return 0;
 316
 317 err_reg:
 318         kfree(max8952);
 319         return ret;
 320 }
 321
 322 static int __devexit max8952_pmic_remove(struct i2c_client *client)
 323 {
 324         struct max8952_data *max8952 = i2c_get_clientdata(client);
 325         struct max8952_platform_data *pdata = max8952->pdata;
 326         struct regulator_dev *rdev = max8952->rdev;
 327
 328         regulator_unregister(rdev);
 329
 330         gpio_free(pdata->gpio_vid0);
 331         gpio_free(pdata->gpio_vid1);
 332         gpio_free(pdata->gpio_en);
 333
 334         kfree(max8952);
 335         return 0;
 336 }
 337
 338 static const struct i2c_device_id max8952_ids[] = {
 339         { "max8952", 0 },
 340         { },
 341 };
 342 MODULE_DEVICE_TABLE(i2c, max8952_ids);
 343
 344 static struct i2c_driver max8952_pmic_driver = {
 345         .probe          = max8952_pmic_probe,
 346         .remove         = __devexit_p(max8952_pmic_remove),
 347         .driver         = {
 348                 .name   = "max8952",
 349         },
 350         .id_table       = max8952_ids,
 351 };
 352
 353 static int __init max8952_pmic_init(void)
 354 {
 355         return i2c_add_driver(&max8952_pmic_driver);
 356 }
 357 subsys_initcall(max8952_pmic_init);
 358
 359 static void __exit max8952_pmic_exit(void)
 360 {
 361         i2c_del_driver(&max8952_pmic_driver);
 362 }
 363 module_exit(max8952_pmic_exit);
 364
 365 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
 366 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
 367 MODULE_LICENSE("GPL");